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28 Cards in this Set
- Front
- Back
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What does the pituitary secrete in response to GnRH?
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FSH/LH
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What cell does LH act on? Causes release of what?
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Leydig cells. Causes release of testosterone.
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What cell does FSH act on? Causes release of what?
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Seminiferous tubules. Causes maturation of sperm and causes release of inhibin and activin.
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What is inhibin? What are its effects?
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Inhibin is released by the seminiferous tubules and has a downregulating affect on the release of LH/FSH from the pituitary.
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What is activin? What are its effects?
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Activin is released by the seminiferous tubules and has a upregulating affect on the release of LH/FSH from the pituitary.
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What downregulates the release of LH/FSH from the pituitary?
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Testosterone.
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GnRH disorder etiology of hypogonadism
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Kallman's syndrome - aplasia of the olfactory ridge, GnRH release defect --> hypogonadism
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What three physical abnormalities in the brain can lead to hypogonadism?
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1. Craniopharyngoma --> panhyopopituitarism --> hypogonadism.
2. Prolactinoma --> direct inhibition of LH/FSH, also has a direct effect on sperm --> hypogonadism 3. Hemochromatosis --> iron deposits in pituitary and messes up function --> hypogonadism. |
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What is the difference between primary and secondary hypogonadism?
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Primary hypogonadism is an elevation of gonadotropins, while secondary hypogonadism is a disorder of low gonadotropins.
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What drugs can cause primary hypogonadism?
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Spironolactone, ketoconazole, antineoplastic drugs.
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Klinefelter's syndrome: incidence
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1:500 men
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Klinefelter's syndrome: genetic abnormality
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47 XXY chromosome due to nondisjunction during gametogenesis or in the zygote during mitosis.
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Klinefelter's syndrome: clinical features
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Infertility
Tall stature and/or eunuchoid habitus Gynecomastia Venous disease Learning disorders - dyslexia Taurodontism (teeth contain more pulp close to surface) Autoimmune disease Thyroid disease |
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Kallman's syndrome: pathogenesis
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Defect in the migration of GnRH neurons from the olfactory placode to the arcuate nucleus of the hthal.
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Kallman's syndrom: demographics
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men > women, familial tendency.
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Fertile enunch syndrome: basic ideas
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Disorder of GnRH release. There is enough gonadotropins to stimuate spermatogenesis, but not enough to virulize peripheral tissues.
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Testicular feminization: phenotype.
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Phenotypic female with amenorrhea. No internal genitalia, labial testes.
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Testicular feminization: significant lab values.
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Testosterone is normal, estradiol and LH are increased.
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Testicular feminization: what is the defect?
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A complete to incomplete defect in the testosterone receptor.
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What affect would a 5-alpha-reductase deficiency have on a person?
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This would affect testosterone --> Dihydrotestosterone.
No beard growth or acne. Marked hypospadias, labial testes |
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What is hypospadias?
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A birth defect in males marked by an abnormal opening of the urethra (urinary meatus)
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What is the general definition of congenital adrenal hyperplasia?
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A group of inherited disorders resulting from an enzymatic defect in the biosynthetic pathway for glucocorticoids and/or mineralocorticoids.
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What is the general idea of the pathogenesis involved with CAH?
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Defects in enzymes --> increase in ACTH --> back up of substances --> diverted to adrenal androgen synthesis.
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What is the most common enzyme deficiency associated with CAH?
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21-hydroxylase
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What would be a significant clinical finding in someone with a 11-beta hydroxylase deficiency?
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HTN. Deoxycortisone will act like a mineralocorticoid.
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GnRH deficiency: treatment?
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GnRH pump to deliver pulsatile dose.
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Management of hypogonadism when fertility is desired.
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HCG (acts like LH) to increase testicular testosterone production --> FSH to initiate spermatogenesis.
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Management of hypogonadism when fertility is not an issue.
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Testosterone replacement.
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